Question

sin 20° + cos 20°
sin 20° - cos 20°
= cot 155°​

Answer 1

Answer:

Prove that

Cos20-sin20/cos20+sin20=tan25

5 years ago

Answers : (1)

Abhishek Doyal

askIITians Faculty

25 Points

cos20-sin20/cos20+sin20

take cos 20 common from numerator and denominator

cos20(1-sin20/cos20)/cos20(1+sin20/cos20)

then cos20 and cos 20 cancelled form numerator and denominator and sin20/cos20=tan20

now remaining part will be

1-tan20/1+tan20 eq 1

one should be written as 1=tan 45 eq2

by eq 1 and eq 2

=tan45-tan20/1-tan45.tan20 eq 3

because tan(A-B)=tanA-tanB/1-tanA.tanB eq 4

by eq 4

eq 3=tan (45-20)= tan25

Step-by-step explanation:

Answer 2

Answer:

Step-by-step explanation: